Site Mobile Navigation

For Good Health, It Helps To Be Rich and Important

Doctors usually evaluate patients' vulnerability to serious disease by inquiring about risk factors like cigarette smoking, obesity, hypertension and high cholesterol.

But they might be better off asking how much money those patients make, how many years they spent in school and where they stand relative to others in their offices and communities.

Scientists have known for decades that poverty translates into higher rates of illness and mortality. But an explosion of research is demonstrating that social class -- as measured not just by income but also by education and other markers of relative status -- is one of the most powerful predictors of health, more powerful than genetics, exposure to carcinogens, even smoking.

What matters is not simply whether a person is rich or poor, college educated or not. Rather, risk for a wide variety of illnesses, including cardiovascular disease, diabetes, arthritis, infant mortality, many infectious diseases and some types of cancer, varies with relative wealth or poverty: the higher the rung on the socioeconomic ladder, the lower the risk. And this relationship holds even at the upper reaches of society, where it might seem that an abundance of resources would even things out.

Social class is an uncomfortable subject for many Americans. ''I think there has been a resistance to thinking about social stratification in our society,'' said Dr. Nancy Adler, professor of medical psychology at the University of California at San Francisco and director of the John T. and Catherine D. MacArthur Foundation Research Network on Socioeconomic Status and Health. Instead, researchers traditionally have focused on health differences between rich and poor, or blacks and whites (unaware, in many cases, that race often served as a proxy for socioeconomic status, since blacks are disproportionately represented in lower income brackets).

But the notion that a mid-level executive with a three-bedroom, split-level in Scarsdale might somehow be more vulnerable to illness than his boss in the five-bedroom colonial a few blocks away seems to have finally captured scientists' attention.

In the past five years, 193 papers addressing aspects of socioeconomic status and health have appeared in scientific journals -- twice the number in the previous five-year period. The National Institutes of Health last year declared research on disparities in health related to social class or minority status one of its highest priorities, said Dr. Norman Anderson, associate director of the N.I.H. And a recent conference in Bethesda, Md., on the topic, sponsored by the New York Academy of Sciences and the MacArthur Foundation network, drew more than 250 participants from a wide variety of disciplines.

What first compelled researchers interest was a now-classic study, begun in the late 1960's, of men in the British civil service. The Whitehall study, directed by Dr. Michael Marmot, director of the International Center for Health and Society at University College London, tracked mortality rates over 10 years for 17,530 male civil service employees.

When the data were analyzed, the researchers were astonished to discover that mortality rates varied continuously and precisely with the men's civil service grade: the higher the classification, the lower the rates of death, regardless of cause.

This finding was as perplexing as it was intriguing. The men all had jobs, and equal access to health care under Britain's national health system. But mortality rates for men in the lowest civil service classification, the researchers found, were three times higher than those for men in the highest grade. And a 25-year follow-up of the Whitehall subjects, some results of which were published in 1996, found the social class gradient persisted well past retirement, even among men into their late 80's.

Subsequent studies demonstrated a similar relationship between socioeconomic status and mortality in the United States and Canada.

What could account for such startling findings? One plausible explanation was that lower-ranked men might engage in more risky behaviors, like smoking. But the same health disparity from pay grade to pay grade that was evident in smokers held for nonsmokers, too. And all coronary risk factors combined, the researchers found, accounted for only a third of the differences between grades.

Stress, or other aspects of psychological life that can have an impact on a person's vulnerability to disease, the Whitehall group reasoned, might also play a role in the results. Prolonged exposure to stress, researchers have found, can lead to abnormalities in immune function and glucose metabolism, and destroy brain cells involved in memory. And studies show that the lower one's social status, the more stressed people feel, and the more stressful events they encounter in their lives.

Dr. Sheldon Cohen, professor of psychology at Carnegie Mellon University in Pittsburgh, has demonstrated a link between social status and vulnerability to infectious disease in male macaque monkeys. In a study carried out in conjunction with primate researchers at Wake Forest University School of Medicine, Dr. Cohen found that males at the lower end of the dominance hierarchy were more susceptible to a cold virus than dominant males.

Dr. Cohen and his colleagues at Carnegie Mellon then replicated those findings in humans. Subjects in the study were asked to rate their relative standing in their community on a social status ladder, then were exposed to mild respiratory virus. People who ranked themselves low on the ladder were more likely to become infected with the virus than those who ranked themselves higher up on the ladder.

In another study, the researchers found that people who had been unemployed for one month or more under highly stressful conditions were 3.8 times more susceptible to a virus than people who were not experiencing a significant stressful situation.

At least in primates, the interaction of stress with social class and illness, however, depends both on the nature of the stress and the context in which it occurs, as demonstrated in a series of studies by Dr. Jay R. Kaplan, a professor of pathology and anthropology at Wake Forest.

An error has occurred. Please try again later.

You are already subscribed to this email.

In a crowded situation where resources are scarce, for example, male monkeys at the lowest end of the dominance hierarchy, who must scramble hardest to survive, are likely to feel the most stress. And in studies of primates in the wild, researchers find that subordinate animals show higher levels of stress hormones.

But when Dr. Kaplan and his colleagues fed male monkeys a ''luxury'' diet, high in fat and cholesterol, and moved them each month for two years into a new group of strange males, it was the dominant animals, forced to reassert their position continually, who suffered the most stress. Under such conditions, Dr. Kaplan finds, dominant males show a hypervigilant response, and have higher rates of coronary artery disease than subordinates.

For humans and primates, a sense of control over life events is intimately related to stress. And control seems to have been one factor at work in the Whitehall study.

In 1985, Dr. Marmot and his colleagues launched Whitehall II, a second large-scale study, which included civil servants of both sexes and which collected more detailed information on the participants.

As part of the study, employees were asked to rate the amount of control they felt over their jobs. Managers also rated the amount of control employees had. Job control, the researchers found, varied inversely with employment grade: the higher the grade, the more control. And the less control employees had, as defined either by their own or managers' ratings, the higher the employees' risk of developing coronary disease. Job control, in fact, accounted for about half the gradient in deaths from pay grade to pay grade.

To some extent, people's ability to withstand stress, and the ways in which they interpret and respond to life events, are shaped by early life, the product of what one social scientist, Dr. Clyde Hertzman of the University of British Columbia, calls ''the long arm of childhood.'' Genetics play a role, as does nutrition. (In the Whitehall study, height -- which varies with social class -- was used as a rough indicator of childhood influences on development, and accounted for a small portion of the association between mortality and employment grade.) And scientists have found that early life experiences -- abuse and neglect, for example -- can alter brain development and influence responses to stressful events.

Any discussion of socioeconomic status in the United States of necessity involves a discussion of race, since the two are entwined in complex, sometimes inextricable, ways. Proportionally, far more African-Americans live in poverty than whites: 28.4 percent of blacks fell below the poverty line in 1996, compared with 11.2 percent of whites, according to Government data. Death rates for African-Americans from all causes are 1.6 times higher than for white Americans, Dr. David R. Williams of the University of Michigan's Institute for Social Research, said at the Bethesda conference.

Life expectancy for blacks and whites also varies. At age 45, a white man can expect to live five years longer than an African-American man, and white women can expect to live 3.7 years longer than their black counterparts.

If socioeconomic status is taken into account, health differences between blacks and whites decrease substantially: Black men in the highest income brackets, for example, have a life expectancy 7.4 years longer than black men in the lowest brackets, Dr. Williams said. White men at top income levels live 6.6 years longer than their lowest-income counterparts.

But race and to some extent sex still have an impact on health that is independent of social class. The gap in infant mortality rates between blacks and whites, for example, actually increases with higher social status. And being black or female discounts some of the advantages afforded by education: white men accrue health advantages with every additional year of schooling they receive. But black men and women, though they also show gains, show them only through high school, according to an analysis of Federal data by Dr. Adler and Dr. Burton Singer of Princeton University's Office of Population Research. White women, the researchers found, continue to gain in health status through college, but unlike white men, do not receive the gains in health bestowed by post-graduate education.

Social exclusion, residential segregation and other expressions of institutional racism magnify the impact of socioeconomic status. Several studies, for example, have shown higher adult and infant mortality rates for people living in segregated areas.

For both blacks and whites, living in a neighborhood where social bonds have eroded may have negative effects on health. Dr. Robert Putnam of Harvard University coined the term ''social capital'' to describe the elements that contribute to social cohesion.

Dr. Ichiro Kawachi, director of the Harvard Center for Society and Health, has explored one aspect of social capital -- interpersonal trust -- and its relationship to national and community rates of illness and death.

Dr. Kawachi and his colleagues correlated mortality rates in states with the percentage of state residents who agreed with the statement, ''Most people would try to take advantage of you if they got the chance.'' Death rates, Dr. Kawachi reported at the Bethesda conference, were strongly linked to level of social trust, with the most mistrustful ratings clustering in southern and northeastern states. Another study, of Chicago neighborhoods, yielded similar findings: neighborhoods in which more residents agreed with the statement ''Neighbors can be trusted'' had lower mortality rates.

Why are neighborhoods or states with higher levels of trust healthier? Dr. Kawachi suggests that in neighborhoods where social trust is high, negative health behaviors -- smoking and alcohol consumption, for example -- might be discouraged through community pressure. Residents in high trust neighborhoods may also share more resources, be more willing to help one another out and offer one another more emotional support. ''It is speculation,'' Dr. Kawachi said, ''but probably these little things add up to quite important health differences.''

Even so, the relationship between social class and health is unlikely to be entirely explained by social capital, or by any other single dimension of life experience. Said Dr. Adler, ''There isn't going to be a single explanation or an easy solution, but we've started mapping out some of the places where we can intervene.''

Correction: June 4, 1999

An article in Science Times on Tuesday about social class as a predictor of health misstated the correlation between employees' perception of job control and employment grade. It was a direct correlation, not an inverse one: the higher the grade, the more perception of control, and therefore the better predictor of good health.

We are continually improving the quality of our text archives. Please send feedback, error reports,
and suggestions to archive_feedback@nytimes.com.

A version of this article appears in print on June 1, 1999, on Page F00001 of the National edition with the headline: For Good Health, It Helps To Be Rich and Important. Order Reprints|Today's Paper|Subscribe